View Full Version : Oxygen sensor elimination

11-03-2009, 06:42 PM

I'm new to tunig Buell but recently bought '03 XB9.
There are many using ECM spy, but I'm lookin an easy way to calibrate injection when used aftermarket exhaust and open intake.
There is Remus Powerizer, TFI, Revtech Stealth are all tunable without dynoruns, but what I'we heard the results are not as good as should. When the chances are made to the air/fuel mix, the oxygen sensor tells the ECM to add more air to keep the mixture in stock settings.
So what we are tryin to do is to make an oxygen sensor eliminator like used in Harleys with, for example, Power Commanders to keep the check engine light out. The O2 sensor eliminator gives a steady Volt amount to ECM to keep the "cheating" settings stable.

I'm not a native english speaker so I hope everyone can understand what I'm after in this case.
Comments, questions, suggestions?

11-03-2009, 08:10 PM
I've never heard of the O2 sensor eliminator you are talking about, but in general all narrow-band O2 sensors (like the one buell uses) operate at the same voltage. So I think you would be safe using one that is designed for a harley motor.

05-24-2010, 11:31 AM
Maybe some Buell techs are on here? When an O2 sensor is disconnected in a car, the pcm assumes a middle value (450mv) maybe just disconnecting it will do the same for the buell ecm? I wish there was someone out there who knew more of how these things operated. I"ve asked a few quetions with no real answers about 02s and the "white wire delete" and no one seems to have a solid answer. Bring on the technical stuff. I love it! There also seems to be a lot of "voodoo" regarding the tps "reset" It's just a Potentiometer and all the ecm wants to see is a specific base voltage at closed throttle...am i right?

05-24-2010, 05:42 PM
ECM's don't want fer nothin'. [smirk]
Throttle Position Sensor, TPS, provides signal to ECM.
ECM combines TPS and Revolutions Per Minute, RPM, as baseline time value (duration) of "on" signal to fuel injector. When TPS is out-of-sync, fuel map references go, too; and bike is out of tune.
ECM's signal to injector is further modified by other variables and/or lookup tables.
Other variables inlude: crankshaft position, Inlet Air Temperature, IAT; Cylinder Heat Temperature, CHT; and Adaptive Fuel Value, AFV.
AFV has its basis in subject signal from O2 sensor.
ECMSpy driven "Tuning Guide" holds the answers Buell Tuning Guide (http://www.ukbeg.com/downloads-view.php?category=7&ukbeg=5e9136c7baa93b90ae99e11960850117).
Haven't looked into this, but will: EcmSpy for Mono User Guide Link (http://www.ecmspy.com/ug_mono/userguide_mono.shtml)

05-27-2010, 08:32 PM
If you want to eliminate the 02 sensor just use ECMSpy and set the O2 activation and O2 learn RPM's to 8000k. Couple changes to the hexidecimal data and very easy to do.

This is how I have my bike running as I use the O2 bung for my wideband.

05-27-2010, 11:41 PM
many ways to do it, but as many had to go back and turn it back of for some correction because of weather and where they ride. some live at sealevel but ride to 6 or 8 k in altitude. the fuel burn changes and with out a way for the ecm to see the loss of oxygen in the Exhause you are running so rich its aweful. many have even fouled their plugs because of this issue with no o2 correction. They have a great map at sealevel with a global correction with afv at 100 while riding but they head up into the mountains and the afv drops to the low *80's.

If you have a widebandand guage in the bike and lock out the O2 you can do this test with a steady rpm at a low aptitude then ride way up and hold the same throttle position. you will see a difference in afr and rpm.

same thing goes for a hot dray day and a cool wet day. hold the same tps position and see what it says.

with the O2 on it will correct things for you making it even. with it off you run whats in the map no matter if its accurate or not.

In drag racing they read the O2 each pass to see what the values are and the afr. same as egt. they are needed for a reason on the street. Its the only tool on the bike for exhaust value correction.
I have ran it both ways off and on for a long while. off is less accurate over time. Yes I have dual WB o2's and dual gauges. altitude,weather and temps affect the maps more than you think. My dual WB have been on my bike a couple years. I have replaced the sensors just because. Dont faqll for the trap you dont need it. unless you ride in a bubble... or always ride in a reletive exact climate. Here in fl we dont have that glory. no altitude issues but its hot one minute the avg the next . dry one to poring rain the next. my darn fuel was moving 2 points Average on the afr because of it with no correction.

my 2 cents from what I see on the gauges on the road over two years of seeing this and many more on the dyno.

maps need to be adjusted to the bike its on not a different bike 1/2 way around the world from you with a different fuel quality at that.

If you remember one thing good marketing can sell a legless blind man binoculars and running shoes. Plus convince him he needed them and it was ok to buy them. Thats what the no O2 is about good marketing. NO big drag or race team goes blind to a track. nor would they run the exact map on the dyno without tweaking it to the actual road work data. once the data is done they log details
how much water in the air
temps track and air
weather pattern

This is a starting point for other days with similar data. then they load that map to the race vehicle. from there they do passes and read the datalog and tweak it per event. O2's are used to do this.

This is the only way to stay spot on. because they dont run O2's they have to manually always tweak the fuel to keep it accurate. FI and carbs.

some of us have been around this stuff a long time. look into how weather and altitude affects fuel burn. see drag race tools for this... it applies to the bikes also and to daily drivers. thats why they went to the fuel and FI to start with to make it simple. you want to race remove the epa settings. make it run where the power is.

05-27-2010, 11:47 PM

old and accurate...

05-30-2012, 11:45 PM
Can someone tell me if my Oxigen Sensor Is malfunctioning. It's value goes up and down really fast. Is this normal?
I have an 05 xb12r firebolt with race ecm KN and pipe. Trying to work on rough idle and level cruse RPM sputter 2200-2700rpm. Thank you for your time and help if possible.http://www.buellxb.com/buell_images/13832_20120530174349_S.jpg

05-30-2012, 11:47 PM
The bottom Line is the O2 sensor